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<head><meta charset="utf-8"><title>weekly meeting 2019-12-05 #54818 · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html">weekly meeting 2019-12-05 #54818</a></h3>

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<a name="182659507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182659507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182659507">(Dec 05 2019 at 13:38)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="897">@T-compiler/meeting</span> ; the triage meeting will be starting in 1 hour 22 minutes.</p>



<a name="182659570"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182659570" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182659570">(Dec 05 2019 at 13:39)</a>:</h4>
<p>I will be doing <a href="#narrow/stream/131828-t-compiler/topic/pre-meeting.20triage.202019-12-05.20.2354818/near/182659529" title="#narrow/stream/131828-t-compiler/topic/pre-meeting.20triage.202019-12-05.20.2354818/near/182659529">pre-triage in a parallel topic</a></p>



<a name="182659601"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182659601" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182659601">(Dec 05 2019 at 13:39)</a>:</h4>
<p>this week we have checkin's scheduled from WG-learning and WG-llvm</p>



<a name="182659661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182659661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182659661">(Dec 05 2019 at 13:40)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> , you around to provide an update from WG-learning?</p>



<a name="182659690"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182659690" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182659690">(Dec 05 2019 at 13:40)</a>:</h4>
<p>(I don't see a zulip stream for wg-learning, maybe I'm overlooking it)</p>



<a name="182659739"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182659739" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182659739">(Dec 05 2019 at 13:41)</a>:</h4>
<p><span class="user-mention" data-user-id="123586">@nagisa</span> , I think last time I asked you about WG-llvm, you noted you had a lot of other things going on in life (i think). Do you think we should try to find a co-lead for WG-llvm?</p>



<a name="182661290"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661290" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661290">(Dec 05 2019 at 14:01)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="116266">Santiago Pastorino</span> , you around to provide an update from WG-learning?</p>
</blockquote>
<p>yes, that happens at the end of the meeting, right?</p>



<a name="182661326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661326">(Dec 05 2019 at 14:01)</a>:</h4>
<blockquote>
<p>(I don't see a zulip stream for wg-learning, maybe I'm overlooking it)</p>
</blockquote>
<p><a class="stream" data-stream-id="196385" href="/#narrow/stream/196385-t-compiler.2Fwg-learning">#t-compiler/wg-learning</a></p>



<a name="182661624"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661624" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661624">(Dec 05 2019 at 14:05)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="123586">nagisa</span> , I think last time I asked you about WG-llvm, you noted you had a lot of other things going on in life (i think). Do you think we should try to find a co-lead for WG-llvm?</p>
</blockquote>
<p>According to <a href="https://github.com/rust-lang/team/blob/master/teams/wg-llvm.toml" target="_blank" title="https://github.com/rust-lang/team/blob/master/teams/wg-llvm.toml">https://github.com/rust-lang/team/blob/master/teams/wg-llvm.toml</a> it seems that I’m the workgroup <span aria-label="sweat smile" class="emoji emoji-1f605" role="img" title="sweat smile">:sweat_smile:</span></p>



<a name="182661815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661815">(Dec 05 2019 at 14:07)</a>:</h4>
<blockquote>
<p>(I don't see a zulip stream for wg-learning, maybe I'm overlooking it)</p>
</blockquote>
<p>This is something that has happening to me as well, the new streams just don’t show up.</p>



<a name="182661858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661858">(Dec 05 2019 at 14:07)</a>:</h4>
<p>and I don't see an announcement for this on <a href="#narrow/stream/122649-announce/topic/new.20streams/near/175794042" title="#narrow/stream/122649-announce/topic/new.20streams/near/175794042">https://rust-lang.zulipchat.com/#narrow/stream/122649-announce/topic/new.20streams/near/175794042</a></p>



<a name="182661873"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661873" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661873">(Dec 05 2019 at 14:07)</a>:</h4>
<p>oh here it is: <a href="#narrow/stream/122649-announce/topic/Streams/near/164077391" title="#narrow/stream/122649-announce/topic/Streams/near/164077391">https://rust-lang.zulipchat.com/#narrow/stream/122649-announce/topic/Streams/near/164077391</a></p>



<a name="182661914"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182661914" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182661914">(Dec 05 2019 at 14:08)</a>:</h4>
<p>topic changed.</p>



<a name="182663671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182663671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182663671">(Dec 05 2019 at 14:28)</a>:</h4>
<p>You don’t get subscribed to new streams by default, they should show up if you click the cog icon next to the “Streams” header on the left sidebar and then the all tab on the dialog that shows up.</p>



<a name="182663704"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182663704" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182663704">(Dec 05 2019 at 14:29)</a>:</h4>
<p>(e.g. that would be the only place that <a class="stream" data-stream-id="216091" href="/#narrow/stream/216091-t-compiler.2Fwg-polymorphization">#t-compiler/wg-polymorphization</a> should show up, I just created it a day or two ago with only a few members by default)</p>



<a name="182664124"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182664124" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182664124">(Dec 05 2019 at 14:34)</a>:</h4>
<p>(seems it still is private though <span class="user-mention" data-user-id="116107">@davidtwco</span> -- edit: maybe not -- edit 2: yay, caching issue probably, force refreshed and it's now working)</p>



<a name="182664212"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182664212" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Esteban Küber <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182664212">(Dec 05 2019 at 14:35)</a>:</h4>
<p>(btw, I'll be airborne during the meeting, wont be able to attend)</p>



<a name="182667015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667015">(Dec 05 2019 at 15:02)</a>:</h4>
<p><span aria-label="construction worker" class="emoji emoji-1f477" role="img" title="construction worker">:construction_worker:</span>  request for bug fix: "Const generic ICE: constant in type had an ignored error: TooGeneric" <a href="https://github.com/rust-lang/rust/issues/66962" target="_blank" title="https://github.com/rust-lang/rust/issues/66962">#66962</a></p>



<a name="182667190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667190">(Dec 05 2019 at 15:03)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="897">@T-compiler/meeting</span>! Add a <span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span> emoji to show you're here :)</p>



<a name="182667270"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667270" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667270">(Dec 05 2019 at 15:04)</a>:</h4>
<p>sorry for starting late; wanted to get through making agenda</p>



<a name="182667290"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667290" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667290">(Dec 05 2019 at 15:04)</a>:</h4>
<p>agenda: <a href="https://hackmd.io/4AaN_0u5Re-OhM48FWg7CQ?both" target="_blank" title="https://hackmd.io/4AaN_0u5Re-OhM48FWg7CQ?both">https://hackmd.io/4AaN_0u5Re-OhM48FWg7CQ?both</a></p>



<a name="182667314"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667314" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667314">(Dec 05 2019 at 15:04)</a>:</h4>
<p>so lets have five minutes for</p>



<a name="182667324"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667324" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667324">(Dec 05 2019 at 15:04)</a>:</h4>
<h2>Announcements</h2>



<a name="182667381"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667381" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667381">(Dec 05 2019 at 15:05)</a>:</h4>
<p>- I'm working on some major refactoring of the expression, statement, and item parsers in librustc_parse</p>



<a name="182667490"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667490" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667490">(Dec 05 2019 at 15:06)</a>:</h4>
<blockquote>
<p>- I'm working on some major refactoring of the expression, statement, and item parsers in librustc_parse</p>
</blockquote>
<p>do you have a WIP branch or open draft PR?, interested in seeing what you're doing :)</p>



<a name="182667518"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667518" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667518">(Dec 05 2019 at 15:06)</a>:</h4>
<p>otherwise please share when you're done</p>



<a name="182667613"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667613" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667613">(Dec 05 2019 at 15:07)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/56231" target="_blank" title="https://github.com/rust-lang/rust/issues/56231">#56231</a> landed which unblocks optimizing MIR while preserving debuginfo for variables (copy propagation can already make two user variables share a MIR local, and inlining works with closure captures now)</p>



<a name="182667728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667728">(Dec 05 2019 at 15:08)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> <a href="https://github.com/rust-lang/rust/pull/66994" target="_blank" title="https://github.com/rust-lang/rust/pull/66994">https://github.com/rust-lang/rust/pull/66994</a> for stmt &amp; expression parser part 1</p>



<a name="182667780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667780">(Dec 05 2019 at 15:09)</a>:</h4>
<p><a href="https://github.com/Centril/rust/tree/item-merge" target="_blank" title="https://github.com/Centril/rust/tree/item-merge">https://github.com/Centril/rust/tree/item-merge</a> for some work on item parsers</p>



<a name="182667794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667794">(Dec 05 2019 at 15:09)</a>:</h4>
<p>but still WIP</p>



<a name="182667867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667867">(Dec 05 2019 at 15:09)</a>:</h4>
<p>okay. If anyone has any more announcements for the team, privmsg me  and we'll allocate time at the end</p>



<a name="182667979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667979">(Dec 05 2019 at 15:10)</a>:</h4>
<p>first up, <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler++-label%3Abeta-accepted" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Abeta-nominated+label%3AT-compiler++-label%3Abeta-accepted">beta-nominations</a></p>



<a name="182667995"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182667995" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182667995">(Dec 05 2019 at 15:10)</a>:</h4>
<p>beta-nom 1/2: "E0023: handle expected != tuple pattern type" <a href="https://github.com/rust-lang/rust/issues/67044" target="_blank" title="https://github.com/rust-lang/rust/issues/67044">#67044</a></p>



<a name="182668178"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668178" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668178">(Dec 05 2019 at 15:13)</a>:</h4>
<p>ah gotta love good old <code>match (e1, e2, e3) ... </code></p>



<a name="182668202"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668202" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668202">(Dec 05 2019 at 15:13)</a>:</h4>
<p>(I'm not saying that sarcastically, though I do know "some people" who have undid code of mine using that sort of pattern)</p>



<a name="182668222"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668222" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668222">(Dec 05 2019 at 15:13)</a>:</h4>
<p><span aria-label="heart" class="emoji emoji-2764" role="img" title="heart">:heart:</span> using more pattern matching</p>



<a name="182668228"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668228" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668228">(Dec 05 2019 at 15:13)</a>:</h4>
<p>anyway looks good beta-accepted</p>



<a name="182668248"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668248" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668248">(Dec 05 2019 at 15:13)</a>:</h4>
<p>(and wohoo, slice patterns, <code>[x, tail @ ..]</code> are almost ready to ship!)</p>



<a name="182668251"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668251" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668251">(Dec 05 2019 at 15:14)</a>:</h4>
<p>beta-nom 2/2: "Fix some issues with attributes on unnamed fields" <a href="https://github.com/rust-lang/rust/issues/66669" target="_blank" title="https://github.com/rust-lang/rust/issues/66669">#66669</a></p>



<a name="182668329"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668329" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668329">(Dec 05 2019 at 15:14)</a>:</h4>
<blockquote>
<p>ah gotta love good old <code>match (e1, e2, e3) ... </code></p>
</blockquote>
<p>heh, I was just thinking "man I always find that pattern hard to read" :P</p>



<a name="182668424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668424">(Dec 05 2019 at 15:15)</a>:</h4>
<p>(but no criticism of the PR, I know others feel differently)</p>



<a name="182668466"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668466" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668466">(Dec 05 2019 at 15:15)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span>  I will go to great lengths to avail myself of slice patterns  ;)</p>



<a name="182668601"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668601" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668601">(Dec 05 2019 at 15:17)</a>:</h4>
<p>of note: PR <a href="https://github.com/rust-lang/rust/issues/66669" target="_blank" title="https://github.com/rust-lang/rust/issues/66669">#66669</a> fixes "tuple structs with all-public fields can not be instantiated if one of the fields has an external attribute" <a href="https://github.com/rust-lang/rust/issues/66555" target="_blank" title="https://github.com/rust-lang/rust/issues/66555">#66555</a>, which is a stable-to-stable regression, and a pretty nasty one at that.</p>



<a name="182668620"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668620" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668620">(Dec 05 2019 at 15:17)</a>:</h4>
<p>so yeah, I think beta-accepted too</p>



<a name="182668653"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668653" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668653">(Dec 05 2019 at 15:17)</a>:</h4>
<p>next, <a href="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Astable-nominated+label%3AT-compiler+-label%3Astable-accepted" target="_blank" title="https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&amp;q=label%3Astable-nominated+label%3AT-compiler+-label%3Astable-accepted">stable-nominations</a></p>



<a name="182668678"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668678" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668678">(Dec 05 2019 at 15:18)</a>:</h4>
<p>I can't really udnerstand <a href="https://github.com/rust-lang/rust/issues/66669" target="_blank" title="https://github.com/rust-lang/rust/issues/66669">#66669</a> but I guess "small-ish, seems good" :)</p>



<a name="182668728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668728">(Dec 05 2019 at 15:18)</a>:</h4>
<p>stable-nom 1/2: "Fix some issues with attributes on unnamed fields" <a href="https://github.com/rust-lang/rust/issues/66669" target="_blank" title="https://github.com/rust-lang/rust/issues/66669">#66669</a></p>



<a name="182668776"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668776" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668776">(Dec 05 2019 at 15:18)</a>:</h4>
<p>i.e. the PR we were just discussing</p>



<a name="182668820"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668820" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668820">(Dec 05 2019 at 15:18)</a>:</h4>
<p>feels potentially more risky for stable?</p>



<a name="182668828"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668828" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668828">(Dec 05 2019 at 15:19)</a>:</h4>
<p>so lets take a moment and double-check this, since if niko says "I can't really understand ..." , its worth pausing, especially for stsble</p>



<a name="182668829"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668829" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668829">(Dec 05 2019 at 15:19)</a>:</h4>
<p>(cause it has hacks?)</p>



<a name="182668850"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182668850" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182668850">(Dec 05 2019 at 15:19)</a>:</h4>
<p>the next release is in two weeks, so backporting to beta now is almost like backporting to stable</p>



<a name="182669052"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669052" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669052">(Dec 05 2019 at 15:20)</a>:</h4>
<p>seems like we can prob just backport to beta</p>



<a name="182669071"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669071" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669071">(Dec 05 2019 at 15:20)</a>:</h4>
<p>but I guess that's release team's decision</p>



<a name="182669085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669085">(Dec 05 2019 at 15:20)</a>:</h4>
<p>just because I don't understand it doesn't mean much, I'm not familiar with that code</p>



<a name="182669099"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669099" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669099">(Dec 05 2019 at 15:20)</a>:</h4>
<p>but the changes are not like an obvious mapping</p>



<a name="182669110"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669110" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669110">(Dec 05 2019 at 15:21)</a>:</h4>
<p>(at least to me)</p>



<a name="182669260"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669260" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669260">(Dec 05 2019 at 15:22)</a>:</h4>
<p>I don't even know what an expansion placeholder is</p>



<a name="182669286"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669286" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669286">(Dec 05 2019 at 15:22)</a>:</h4>
<p>and that's like, all of the PR</p>



<a name="182669332"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669332" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669332">(Dec 05 2019 at 15:23)</a>:</h4>
<p>heh yes</p>



<a name="182669342"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669342" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669342">(Dec 05 2019 at 15:23)</a>:</h4>
<p>I think we can trust the reviewers, right?</p>



<a name="182669380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669380">(Dec 05 2019 at 15:23)</a>:</h4>
<p>so on the one hand, since release is so close, a beta approval is essentially like a stable-approval</p>



<a name="182669414"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669414" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669414">(Dec 05 2019 at 15:23)</a>:</h4>
<p>so that's an argument for just using same approval decision for both. But its not a great argument.</p>



<a name="182669513"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669513" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669513">(Dec 05 2019 at 15:24)</a>:</h4>
<p>I am willing to trust reviewers. And this does seem like a pretty bad bug, i.e. worth  fixing</p>



<a name="182669537"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669537" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669537">(Dec 05 2019 at 15:24)</a>:</h4>
<p>(t-compiler is supposed to do technical reviews for stable approvals &amp; assess risk, but from T-release's POV I believe we said that a point release is unlikely 2 weeks to a new release)</p>



<a name="182669589"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669589" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669589">(Dec 05 2019 at 15:25)</a>:</h4>
<p>(ignore me)</p>



<a name="182669726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669726">(Dec 05 2019 at 15:26)</a>:</h4>
<p>okay well lets wrap this up</p>



<a name="182669755"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669755" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669755">(Dec 05 2019 at 15:26)</a>:</h4>
<p>the main argument against a stable backport is that this contains self-described Hacks</p>



<a name="182669770"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669770" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669770">(Dec 05 2019 at 15:26)</a>:</h4>
<p>(I trust the reviewrs, I'm <span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span> to backport)</p>



<a name="182669786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669786">(Dec 05 2019 at 15:26)</a>:</h4>
<p>but I think those Hacks are likely to live on, until someone goes through and, like, re-writes all of this</p>



<a name="182669807"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669807" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669807">(Dec 05 2019 at 15:27)</a>:</h4>
<p>so I too am <span aria-label="thumbs up" class="emoji emoji-1f44d" role="img" title="thumbs up">:thumbs_up:</span> to backport</p>



<a name="182669844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669844">(Dec 05 2019 at 15:27)</a>:</h4>
<p>so okay, lets go with stable-accepted on PR <a href="https://github.com/rust-lang/rust/issues/66669" target="_blank" title="https://github.com/rust-lang/rust/issues/66669">#66669</a></p>



<a name="182669869"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669869" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669869">(Dec 05 2019 at 15:27)</a>:</h4>
<p>stable-nom 2/2: "Do not ICE in <code>if</code> without <code>else</code> in <code>async fn</code>" <a href="https://github.com/rust-lang/rust/issues/66391" target="_blank" title="https://github.com/rust-lang/rust/issues/66391">#66391</a></p>



<a name="182669953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182669953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182669953">(Dec 05 2019 at 15:28)</a>:</h4>
<p>it would be nice if we actually <em>knew</em> if this fixes <a href="https://github.com/rust-lang/rust/issues/66618" target="_blank" title="https://github.com/rust-lang/rust/issues/66618">#66618</a>.</p>



<a name="182670160"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670160" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670160">(Dec 05 2019 at 15:30)</a>:</h4>
<p>it seems safe enough, in an case</p>



<a name="182670162"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670162" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670162">(Dec 05 2019 at 15:30)</a>:</h4>
<p>it certainly seems very low risk</p>



<a name="182670165"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670165" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670165">(Dec 05 2019 at 15:30)</a>:</h4>
<p>stable-accepted</p>



<a name="182670195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670195">(Dec 05 2019 at 15:31)</a>:</h4>
<p>I didn't have time today to traverse the P-high issues</p>



<a name="182670215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670215">(Dec 05 2019 at 15:31)</a>:</h4>
<p>and we're not going to do it live, despite what Bill O'Reilly might say</p>



<a name="182670237"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670237" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670237">(Dec 05 2019 at 15:31)</a>:</h4>
<blockquote>
<p>it would be nice if we actually knew if this fixes <a href="https://github.com/rust-lang/rust/issues/66618" target="_blank" title="https://github.com/rust-lang/rust/issues/66618">#66618</a>.</p>
</blockquote>
<p>it ICEs on stable and beta, not on nightly</p>



<a name="182670244"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670244" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670244">(Dec 05 2019 at 15:31)</a>:</h4>
<p>(what's the reference?)</p>



<a name="182670264"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670264" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670264">(Dec 05 2019 at 15:31)</a>:</h4>
<p>I'll just mention we have 44 open P-high issues and 25 unassigned open P-high issues</p>



<a name="182670338"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670338" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670338">(Dec 05 2019 at 15:32)</a>:</h4>
<blockquote>
<p>(what's the reference?)</p>
</blockquote>
<p>letmegooglethatforyou</p>



<a name="182670391"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670391" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670391">(Dec 05 2019 at 15:32)</a>:</h4>
<p>anyway that's all a way for me to just slide directly to Nominated issues</p>



<a name="182670401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670401">(Dec 05 2019 at 15:32)</a>:</h4>
<p>see agenda: <a href="https://hackmd.io/4AaN_0u5Re-OhM48FWg7CQ?view#Nominated-Issues" target="_blank" title="https://hackmd.io/4AaN_0u5Re-OhM48FWg7CQ?view#Nominated-Issues">https://hackmd.io/4AaN_0u5Re-OhM48FWg7CQ?view#Nominated-Issues</a></p>



<a name="182670437"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670437" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670437">(Dec 05 2019 at 15:33)</a>:</h4>
<p>I've curated five nominated issues for today</p>



<a name="182670464"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670464" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670464">(Dec 05 2019 at 15:33)</a>:</h4>
<p>nom 1/5: "Regression in Error conversion from Infallible" <a href="https://github.com/rust-lang/rust/issues/66757" target="_blank" title="https://github.com/rust-lang/rust/issues/66757">#66757</a></p>



<a name="182670492"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670492" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670492">(Dec 05 2019 at 15:33)</a>:</h4>
<p>seven options are laid out in <a href="https://github.com/rust-lang/rust/issues/66757#issuecomment-559771169" target="_blank" title="https://github.com/rust-lang/rust/issues/66757#issuecomment-559771169">this  comment</a></p>



<a name="182670509"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670509" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670509">(Dec 05 2019 at 15:34)</a>:</h4>
<p>Ah yeah. I think we need to take action quickly here. I am inclined to revert while we work it out.</p>



<a name="182670559"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670559" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670559">(Dec 05 2019 at 15:34)</a>:</h4>
<p>the actual decision won't be made here alone; or at least, some options also need T-lang approval</p>



<a name="182670569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670569">(Dec 05 2019 at 15:34)</a>:</h4>
<p>but I figured it would be good to at least take temperature of people here</p>



<a name="182670595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670595">(Dec 05 2019 at 15:34)</a>:</h4>
<p>(I am reminded I had a comment started..somewhere..suggesting how we could adjust type fallback in more detail; not sure yet if I like the idea)</p>



<a name="182670627"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670627" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670627">(Dec 05 2019 at 15:34)</a>:</h4>
<p>(just saying "revert" is not precise enough; at least three options include that word)</p>



<a name="182670650"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670650" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670650">(Dec 05 2019 at 15:35)</a>:</h4>
<p>I am personally included to go with option 7: "We revert Infallible to an empty enum and the stabilization of the never type"</p>



<a name="182670676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670676">(Dec 05 2019 at 15:35)</a>:</h4>
<p>I might be biased, but I'm in favor of 1/3.</p>



<a name="182670677"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670677" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670677">(Dec 05 2019 at 15:35)</a>:</h4>
<p>that is, I don't see a reason to rush <code>!</code> out the door</p>



<a name="182670815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670815">(Dec 05 2019 at 15:36)</a>:</h4>
<p>still reading niko's last comment tho</p>



<a name="182670823"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670823" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670823">(Dec 05 2019 at 15:36)</a>:</h4>
<p>if other people have different opinions, I guess post them on the issue</p>



<a name="182670858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670858">(Dec 05 2019 at 15:37)</a>:</h4>
<blockquote>
<p>I am personally included to go with option 7: "We revert Infallible to an empty enum and the stabilization of the never type"</p>
</blockquote>
<p>yes, sorry, this is what I meant</p>



<a name="182670894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670894">(Dec 05 2019 at 15:37)</a>:</h4>
<p>In any case lets move along. I don't think this needs synchronous discussion amongst T-compiler</p>



<a name="182670934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182670934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182670934">(Dec 05 2019 at 15:37)</a>:</h4>
<p>nom 2/5: "Necromancing (putting back some removed error codes explanations)" <a href="https://github.com/rust-lang/rust/issues/66836" target="_blank" title="https://github.com/rust-lang/rust/issues/66836">#66836</a></p>



<a name="182671024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671024">(Dec 05 2019 at 15:38)</a>:</h4>
<p>the high level story here is as imperio put it in the PR: "Even if the error code isn't used by the compiler anymore, we should keep the explanations in case people using old versions of the compiler want to read them."</p>



<a name="182671058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671058">(Dec 05 2019 at 15:38)</a>:</h4>
<p>I agree people reading old diagnostics may want the explanatory information</p>



<a name="182671062"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671062" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671062">(Dec 05 2019 at 15:38)</a>:</h4>
<p>Also, so that the error numbers are not reused in the future.</p>



<a name="182671073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671073">(Dec 05 2019 at 15:38)</a>:</h4>
<p>but I don't think it needs to live in the compiler object code (binary and libraries)</p>



<a name="182671088"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671088" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671088">(Dec 05 2019 at 15:39)</a>:</h4>
<p><em>reserving</em> the errors number is a fine idea to me</p>



<a name="182671090"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671090" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671090">(Dec 05 2019 at 15:39)</a>:</h4>
<p><span class="user-mention" data-user-id="123586">@nagisa</span>  we have a system for that</p>



<a name="182671138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671138">(Dec 05 2019 at 15:39)</a>:</h4>
<p>keeping old error numbers ostensibly is technical debt and keeps us from e.g using a more tree-like structure that <span class="user-mention" data-user-id="119009">@eddyb</span> wants</p>



<a name="182671156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671156">(Dec 05 2019 at 15:39)</a>:</h4>
<p><span class="user-mention" data-user-id="126931">@centril</span> in my memory the system was to keep the numbers in in the macros, with or without explanations. From the PR it appears to be re-adding the numbers back.</p>



<a name="182671160"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671160" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671160">(Dec 05 2019 at 15:39)</a>:</h4>
<p>we sometimes treat error codes as if they're a deliberate diagnostic catalog system</p>



<a name="182671213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671213">(Dec 05 2019 at 15:40)</a>:</h4>
<blockquote>
<p>keeping old error numbers ostensibly is technical debt and keeps us from e.g using a more tree-like structure that <span class="user-mention silent" data-user-id="119009">eddyb</span> wants</p>
</blockquote>
<p>wait, that sounds like we should not even reserve the error numbers?</p>



<a name="182671253"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671253" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671253">(Dec 05 2019 at 15:40)</a>:</h4>
<p>is this not something we can resolve quickly? Do we need a design meeting about our long-term approach to error diagnostic cataloguing?</p>



<a name="182671255"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671255" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671255">(Dec 05 2019 at 15:40)</a>:</h4>
<p>and without revising every single diagnostic to improve this, the meaningfulness of individual error codes is all over the place</p>



<a name="182671269"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671269" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671269">(Dec 05 2019 at 15:41)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span>  my point is that if we readd these then what's a pretty strong "let's not change into a tree structure for existing diagnostics because it will make links outdated"</p>



<a name="182671270"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671270" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671270">(Dec 05 2019 at 15:41)</a>:</h4>
<p>I'm trying to understand the use case exactly</p>



<a name="182671272"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671272" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671272">(Dec 05 2019 at 15:41)</a>:</h4>
<p>if I'm using an old version of the compiler</p>



<a name="182671285"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671285" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671285">(Dec 05 2019 at 15:41)</a>:</h4>
<p>then why am I running <code>--explain</code> on the new one?</p>



<a name="182671288"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671288" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671288">(Dec 05 2019 at 15:41)</a>:</h4>
<blockquote>
<p>if I'm using an old version of the compiler</p>
</blockquote>
<p>I don't think this made sense</p>



<a name="182671293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671293">(Dec 05 2019 at 15:41)</a>:</h4>
<p>I guess maybe it's running on travis or something</p>



<a name="182671306"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671306" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671306">(Dec 05 2019 at 15:41)</a>:</h4>
<p>I was trying to be charitable by rephrasing in my high level description</p>



<a name="182671307"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671307" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671307">(Dec 05 2019 at 15:41)</a>:</h4>
<p>but it seems like it's easy enough to use rustup</p>



<a name="182671314"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671314" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671314">(Dec 05 2019 at 15:41)</a>:</h4>
<p>by acting like you're looking at an old diagnostic (e.g. in a blog post)</p>



<a name="182671404"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671404" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671404">(Dec 05 2019 at 15:42)</a>:</h4>
<p>blogs &amp; stack overflow do seem more likely</p>



<a name="182671412"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671412" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671412">(Dec 05 2019 at 15:42)</a>:</h4>
<p>The error codes were added so that they are easibly searchable on the internet and I suppose if you found E123 on stackoverflow and wanted to read its explanation, it doesn’t matter which version of the compiler you’re running</p>



<a name="182671417"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671417" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671417">(Dec 05 2019 at 15:42)</a>:</h4>
<p>but still, you can google and there are archives</p>



<a name="182671426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671426">(Dec 05 2019 at 15:42)</a>:</h4>
<p>IMO exposing error codes to users was a mistake because some now expect to be able to use them as something that they're really not</p>



<a name="182671436"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671436" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671436">(Dec 05 2019 at 15:42)</a>:</h4>
<p>so there it sounds like there are two topics here:</p>



<a name="182671438"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671438" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671438">(Dec 05 2019 at 15:42)</a>:</h4>
<p>OK. I don't really have a strong opinion on this, but I think that saying "this error code is no longer emitted by the compiler" probably suffices <em>personally</em></p>



<a name="182671451"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671451" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671451">(Dec 05 2019 at 15:42)</a>:</h4>
<ol>
<li>are error codes meant to be reserved for all time?</li>
</ol>



<a name="182671462"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671462" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671462">(Dec 05 2019 at 15:43)</a>:</h4>
<p>and I keep seeing error codes in places where two-three words would be infinitely more useful</p>



<a name="182671471"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671471" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671471">(Dec 05 2019 at 15:43)</a>:</h4>
<ol start="2">
<li>are the diagnostic <em>messages</em> (for reserved error codes) meant to be reserved for all time?</li>
</ol>



<a name="182671494"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671494" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671494">(Dec 05 2019 at 15:43)</a>:</h4>
<ol start="2">
<li>ouch... no diagnostics improvements for you <span aria-label="sweat smile" class="emoji emoji-1f605" role="img" title="sweat smile">:sweat_smile:</span></li>
</ol>



<a name="182671520"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671520" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671520">(Dec 05 2019 at 15:43)</a>:</h4>
<p>well, the "extended" descriptions etc</p>



<a name="182671524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671524">(Dec 05 2019 at 15:43)</a>:</h4>
<p>well, 2 modulo "improvements"</p>



<a name="182671542"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671542" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671542">(Dec 05 2019 at 15:44)</a>:</h4>
<p>anyway this is taking more time than I expected.</p>



<a name="182671587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671587">(Dec 05 2019 at 15:44)</a>:</h4>
<p>I personally don't even bother with error codes for new diagnostics myself</p>



<a name="182671589"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671589" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671589">(Dec 05 2019 at 15:44)</a>:</h4>
<p>but I suspect we should collective r- this</p>



<a name="182671617"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671617" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671617">(Dec 05 2019 at 15:44)</a>:</h4>
<p>and say "we're not sure what our exact plan is, but its probably not this."</p>



<a name="182671643"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671643" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671643">(Dec 05 2019 at 15:44)</a>:</h4>
<p>maybe a good design topic</p>



<a name="182671646"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671646" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671646">(Dec 05 2019 at 15:44)</a>:</h4>
<p>cc <span class="user-mention" data-user-id="210316">@GuillaumeGomez</span></p>



<a name="182671665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671665">(Dec 05 2019 at 15:44)</a>:</h4>
<p>that is, I think it'd be worth trying to formulate a plan around diagnostic codes</p>



<a name="182671677"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671677" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671677">(Dec 05 2019 at 15:44)</a>:</h4>
<p>like <span class="user-mention" data-user-id="119009">@eddyb</span> I have my concerns :)</p>



<a name="182671683"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671683" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671683">(Dec 05 2019 at 15:45)</a>:</h4>
<p>(and around internationalization!)</p>



<a name="182671698"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671698" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671698">(Dec 05 2019 at 15:45)</a>:</h4>
<blockquote>
<p>I personally don't even bother with error codes for new diagnostics myself</p>
</blockquote>
<p>and then there are comments like this</p>



<a name="182671708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671708">(Dec 05 2019 at 15:45)</a>:</h4>
<p>(with which I sympathsize)</p>



<a name="182671709"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671709" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671709">(Dec 05 2019 at 15:45)</a>:</h4>
<p>okay. maybe eddyb can draft whatever this error-code tree is</p>



<a name="182671723"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671723" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671723">(Dec 05 2019 at 15:45)</a>:</h4>
<p>what we <em>should've</em> done (hindsight 2020) is do a top-down error grouping, and then reduce the coarseness of the granularity over time, to the point where individual diagnostics are designed to be <em>meaningfully</em> distinct and can be associated their own identifier</p>



<a name="182671727"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671727" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671727">(Dec 05 2019 at 15:45)</a>:</h4>
<p>I didn't even know it was an option to not use an error code</p>



<a name="182671738"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671738" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671738">(Dec 05 2019 at 15:45)</a>:</h4>
<p>idk what <span class="user-mention" data-user-id="126931">@centril</span> meant, btw, <span class="user-mention" data-user-id="116083">@pnkfelix</span></p>



<a name="182671757"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671757" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671757">(Dec 05 2019 at 15:45)</a>:</h4>
<blockquote>
<p>and then there are comments like this</p>
</blockquote>
<p>to elaborate, it's a time sink, better spent on improving the diagnostics in rustc itself</p>



<a name="182671771"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671771" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671771">(Dec 05 2019 at 15:45)</a>:</h4>
<p><span class="user-mention" data-user-id="132040">@Manish Goregaokar</span> was talking about some stuff that has had more thought put into it than I have spent on the matter</p>



<a name="182671773"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671773" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671773">(Dec 05 2019 at 15:45)</a>:</h4>
<p><span class="user-mention" data-user-id="119009">@eddyb</span> meant by?</p>



<a name="182671784"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671784" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671784">(Dec 05 2019 at 15:46)</a>:</h4>
<p>the "tree" thing</p>



<a name="182671843"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671843" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671843">(Dec 05 2019 at 15:46)</a>:</h4>
<p>okay lets move along</p>



<a name="182671858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671858">(Dec 05 2019 at 15:46)</a>:</h4>
<p>maybe allocate a separate zulip topic for this</p>



<a name="182671870"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671870" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671870">(Dec 05 2019 at 15:46)</a>:</h4>
<p>after meeting is over</p>



<a name="182671875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671875">(Dec 05 2019 at 15:46)</a>:</h4>
<p><span class="user-mention" data-user-id="119009">@eddyb</span> a more semantic categorization of errors</p>



<a name="182671909"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671909" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671909">(Dec 05 2019 at 15:46)</a>:</h4>
<p>nom 3/5: "[WIP] [DO NOT MERGE] combine <a href="https://github.com/rust-lang/rust/issues/66020" target="_blank" title="https://github.com/rust-lang/rust/issues/66020">#66020</a> and <a href="https://github.com/rust-lang/rust/issues/66821" target="_blank" title="https://github.com/rust-lang/rust/issues/66821">#66821</a>." <a href="https://github.com/rust-lang/rust/issues/66838" target="_blank" title="https://github.com/rust-lang/rust/issues/66838">#66838</a></p>



<a name="182671938"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671938" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671938">(Dec 05 2019 at 15:47)</a>:</h4>
<p><span class="user-mention" data-user-id="119009">@eddyb</span> can you provide background context here?</p>



<a name="182671977"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671977" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671977">(Dec 05 2019 at 15:47)</a>:</h4>
<p>heh "Even if these PRs may not be perfectly sound" well there's a scary note</p>



<a name="182671981"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671981" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671981">(Dec 05 2019 at 15:47)</a>:</h4>
<p>that probably doesn't need to be nominated?</p>



<a name="182671997"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182671997" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182671997">(Dec 05 2019 at 15:47)</a>:</h4>
<p>"cc @rust-lang/compiler @rust-lang/wg-traits I'm nominating this for discussion, so that we can find a way to land at least some of these changes."</p>



<a name="182672011"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672011" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672011">(Dec 05 2019 at 15:47)</a>:</h4>
<p>maybe it was meant to be targetted at just wg-traits?</p>



<a name="182672012"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672012" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672012">(Dec 05 2019 at 15:47)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> do you want to provide context? or should I</p>



<a name="182672058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672058">(Dec 05 2019 at 15:48)</a>:</h4>
<p>(I think the approach is sound, though as I told <span class="user-mention" data-user-id="119009">@eddyb</span> I was kind of holding that optimization in reserve for chalk <span aria-label="stuck out tongue" class="emoji emoji-1f61d" role="img" title="stuck out tongue">:stuck_out_tongue:</span>)</p>



<a name="182672064"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672064" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672064">(Dec 05 2019 at 15:48)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="692">@WG-traits</span>  ^</p>



<a name="182672076"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672076" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672076">(Dec 05 2019 at 15:48)</a>:</h4>
<p>(but it's right to do it now)</p>



<a name="182672085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672085">(Dec 05 2019 at 15:48)</a>:</h4>
<p>Given the number of soundness holes in the type system specifically I think we should be careful with changing WF rules themselves</p>



<a name="182672095"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672095" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672095">(Dec 05 2019 at 15:48)</a>:</h4>
<p>that's not what this PR is</p>



<a name="182672113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672113">(Dec 05 2019 at 15:48)</a>:</h4>
<p>the important thing is that there's huge perf wins that we've been just not getting for years</p>



<a name="182672120"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> GuillaumeGomez <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672120">(Dec 05 2019 at 15:48)</a>:</h4>
<p>hi</p>



<a name="182672126"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672126" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672126">(Dec 05 2019 at 15:48)</a>:</h4>
<p>basically the tl;dr is that we used to only cache results without considering the "environment" (i.e., where clauses in scope) -- therefore, we only cached if there are no where clauses in scope</p>



<a name="182672140"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672140" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> GuillaumeGomez <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672140">(Dec 05 2019 at 15:49)</a>:</h4>
<p>so to answer: yes they are supposed reserved ad vitam</p>



<a name="182672141"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672141" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672141">(Dec 05 2019 at 15:49)</a>:</h4>
<p>but one of the ideas of chalk was to incorporate the environment into the cache key</p>



<a name="182672159"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672159" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672159">(Dec 05 2019 at 15:49)</a>:</h4>
<p>which is the approach we're using now in borrowck etc</p>



<a name="182672162"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672162" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672162">(Dec 05 2019 at 15:49)</a>:</h4>
<p>this: "avoid checking Trait's predicates for WF(&lt;T as Trait&gt;::X). " sounds like it could be changing WF rules</p>



<a name="182672166"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672166" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672166">(Dec 05 2019 at 15:49)</a>:</h4>
<p>eddyb is extending that</p>



<a name="182672191"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672191" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672191">(Dec 05 2019 at 15:49)</a>:</h4>
<p>ah, ok, I didn't realize that commit was in there too :)</p>



<a name="182672192"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672192" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672192">(Dec 05 2019 at 15:49)</a>:</h4>
<p>my bad</p>



<a name="182672196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> GuillaumeGomez <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672196">(Dec 05 2019 at 15:49)</a>:</h4>
<p>also, a long time ago, we wanted to replace the long explanations with some more interactive explanations</p>



<a name="182672207"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672207" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672207">(Dec 05 2019 at 15:49)</a>:</h4>
<p>that's the thing, this PR is doing both</p>



<a name="182672219"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672219" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672219">(Dec 05 2019 at 15:49)</a>:</h4>
<p>there are 3 PRs, no?</p>



<a name="182672222"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672222" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672222">(Dec 05 2019 at 15:49)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> the nominated PR is explicitly a combination of the two fix attempts</p>



<a name="182672226"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672226" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> GuillaumeGomez <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672226">(Dec 05 2019 at 15:49)</a>:</h4>
<p>they'd take the erroneous user code and based on it, generate some specific explanations</p>



<a name="182672228"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672228" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672228">(Dec 05 2019 at 15:49)</a>:</h4>
<p>ok, that one I have to ponder a bit, I still favor a different (harder) approach</p>



<a name="182672231"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672231" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672231">(Dec 05 2019 at 15:49)</a>:</h4>
<p>"this PR"  is rather ambiguous :P</p>



<a name="182672235"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672235" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672235">(Dec 05 2019 at 15:49)</a>:</h4>
<p>(sorry for the confusion)</p>



<a name="182672295"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672295" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672295">(Dec 05 2019 at 15:50)</a>:</h4>
<p>"this PR" == the PR that <span class="user-mention" data-user-id="116083">@pnkfelix</span> cited</p>



<a name="182672332"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672332" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672332">(Dec 05 2019 at 15:50)</a>:</h4>
<blockquote>
<p>they'd take the erroneous user code and based on it, generate some specific explanations</p>
</blockquote>
<p><span class="user-mention" data-user-id="210316">@GuillaumeGomez</span> okay, sorry for misleading you; we've put that topic aside</p>



<a name="182672354"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672354" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672354">(Dec 05 2019 at 15:50)</a>:</h4>
<p>(backscroll)</p>



<a name="182672360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672360">(Dec 05 2019 at 15:50)</a>:</h4>
<p>if the two PRs are really orthogonal, we can just merge the uncontroversial one for now?</p>



<a name="182672374"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672374" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> GuillaumeGomez <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672374">(Dec 05 2019 at 15:50)</a>:</h4>
<p>I just received the messages<br>
slow connection T_T</p>



<a name="182672376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672376">(Dec 05 2019 at 15:50)</a>:</h4>
<p>(though I agree, <span class="user-mention" data-user-id="210316">@GuillaumeGomez</span>, that generating "extended' errors instead of having separate codes seems better)</p>



<a name="182672396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> GuillaumeGomez <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672396">(Dec 05 2019 at 15:50)</a>:</h4>
<p>sorry for the disturbance, leaving again o/</p>



<a name="182672422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672422">(Dec 05 2019 at 15:51)</a>:</h4>
<blockquote>
<p>if the two PRs are really orthogonal, we can just merge the uncontroversial one for now?</p>
</blockquote>
<p>yes, <a href="https://github.com/rust-lang/rust/issues/66821" target="_blank" title="https://github.com/rust-lang/rust/issues/66821">#66821</a> has become even less controversial since the nomination</p>



<a name="182672428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672428">(Dec 05 2019 at 15:51)</a>:</h4>
<blockquote>
<p>if the two PRs are really orthogonal, we can just merge the uncontroversial one for now?</p>
</blockquote>
<p>I was assuming we would start with the 'extended caching' ones and I'll try to put more energy into validating the final one, or experimenting with an alternae approach</p>



<a name="182672436"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672436" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672436">(Dec 05 2019 at 15:51)</a>:</h4>
<p>okay</p>



<a name="182672460"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672460" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672460">(Dec 05 2019 at 15:51)</a>:</h4>
<p>I think there's general agreement that we should invest effort in landing the caching chasnges</p>



<a name="182672471"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672471" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672471">(Dec 05 2019 at 15:51)</a>:</h4>
<p>but hold off on the WF changes?</p>



<a name="182672500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672500">(Dec 05 2019 at 15:51)</a>:</h4>
<p>(maybe "general agreement" is too strong a word)</p>



<a name="182672552"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672552" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672552">(Dec 05 2019 at 15:52)</a>:</h4>
<p>I think that's fine with me and sufficient for the client I did this for</p>



<a name="182672577"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672577" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672577">(Dec 05 2019 at 15:52)</a>:</h4>
<p>the wins are in the same ballpark</p>



<a name="182672585"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672585" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672585">(Dec 05 2019 at 15:52)</a>:</h4>
<p>I really just mean that its premature to discuss WF changes in <em>this</em> meeting</p>



<a name="182672596"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672596" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672596">(Dec 05 2019 at 15:52)</a>:</h4>
<p>okay great</p>



<a name="182672608"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672608" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672608">(Dec 05 2019 at 15:52)</a>:</h4>
<p>lets move along then</p>



<a name="182672609"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672609" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672609">(Dec 05 2019 at 15:52)</a>:</h4>
<p>(I'm basically a bit wary of "I think it's sound" reasoning not checked by things consistent-as-a-logic, because I feel we've gotten this wrong before...)</p>



<a name="182672636"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672636" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672636">(Dec 05 2019 at 15:52)</a>:</h4>
<blockquote>
<p>(I'm basically a bit wary of "I think it's sound" reasoning not checked by things consistent-as-a-logic, because I feel we've gotten this wrong before...)</p>
</blockquote>
<p>see 1.0</p>



<a name="182672650"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672650" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672650">(Dec 05 2019 at 15:52)</a>:</h4>
<p>nom 4/5: another eddyb PR "rustc: include ParamEnv in global trait select/eval cache keys." <a href="https://github.com/rust-lang/rust/issues/66963" target="_blank" title="https://github.com/rust-lang/rust/issues/66963">#66963</a></p>



<a name="182672667"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672667" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672667">(Dec 05 2019 at 15:53)</a>:</h4>
<p><span class="user-mention" data-user-id="119009">@eddyb</span>  as in Rust 1.0?</p>



<a name="182672678"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672678" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672678">(Dec 05 2019 at 15:53)</a>:</h4>
<p>(yes)</p>



<a name="182672701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672701">(Dec 05 2019 at 15:53)</a>:</h4>
<p>oh this one is nominated because the caching PR uncovered a bug</p>



<a name="182672720"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672720" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672720">(Dec 05 2019 at 15:53)</a>:</h4>
<p>what is here to discuss? Seems like perf regressions are acceptable?</p>



<a name="182672745"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672745" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672745">(Dec 05 2019 at 15:53)</a>:</h4>
<p>we were poisoning trait caches with the wrong Reveal mode sometimes</p>



<a name="182672803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672803">(Dec 05 2019 at 15:54)</a>:</h4>
<p>this could mean that type-checking could e.g. see <code>impl Trait</code> concrete types, potentially</p>



<a name="182672836"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672836" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672836">(Dec 05 2019 at 15:54)</a>:</h4>
<blockquote>
<p>(yes)</p>
</blockquote>
<p>not sure what you mean by seeing 1.0... that practicality and shipping requires taking risks?</p>



<a name="182672844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672844">(Dec 05 2019 at 15:54)</a>:</h4>
<p>it's unclear yet what the fallout would be, we're mostly saved by the compiler still doing things in a certain order</p>



<a name="182672845"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672845" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672845">(Dec 05 2019 at 15:54)</a>:</h4>
<p>do you think there is a further latent bug here that is not being addressed by this PR ?</p>



<a name="182672883"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672883" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672883">(Dec 05 2019 at 15:54)</a>:</h4>
<blockquote>
<blockquote>
<p>(yes)</p>
</blockquote>
<p>not sure what you mean by seeing 1.0... that practicality and shipping requires taking risks?</p>
</blockquote>
<p>the first year after 1.0 was spent fixing the trait system. IIRC the WF system was added some time after 1.0</p>



<a name="182672934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182672934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182672934">(Dec 05 2019 at 15:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> doubtful, unless there is more than the <code>Reveal</code> that can affect the result that's being cached (I'm not aware of anything, but I'm not a trait system expert)</p>



<a name="182673043"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673043" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673043">(Dec 05 2019 at 15:56)</a>:</h4>
<p>okay well I'm not sure what there is for the team to discuss here. Especially if the caching changes improve things more than PR <a href="https://github.com/rust-lang/rust/issues/66963" target="_blank" title="https://github.com/rust-lang/rust/issues/66963">#66963</a> regresses them. :)</p>



<a name="182673091"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673091" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673091">(Dec 05 2019 at 15:56)</a>:</h4>
<p>I nominated it because it scared me but we're <em>probably</em> fine</p>



<a name="182673094"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673094" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673094">(Dec 05 2019 at 15:56)</a>:</h4>
<p>I mostly want to make sure we get to the last nomination</p>



<a name="182673115"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673115" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673115">(Dec 05 2019 at 15:56)</a>:</h4>
<p>okay lets push on, I don't see people clamoring to burn you at the stake</p>



<a name="182673132"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673132" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673132">(Dec 05 2019 at 15:56)</a>:</h4>
<blockquote>
<p>I nominated it because it scared me but we're probably fine</p>
</blockquote>
<p>in the sense that it might cause breakage?</p>



<a name="182673146"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673146">(Dec 05 2019 at 15:57)</a>:</h4>
<p>nom 5/5: "Limit dylib symbols" <a href="https://github.com/rust-lang/rust/issues/59752" target="_blank" title="https://github.com/rust-lang/rust/issues/59752">#59752</a></p>



<a name="182673158"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673158" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673158">(Dec 05 2019 at 15:57)</a>:</h4>
<p>this is nominated for revert</p>



<a name="182673170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673170">(Dec 05 2019 at 15:57)</a>:</h4>
<blockquote>
<blockquote>
<p>I nominated it because it scared me but we're probably fine</p>
</blockquote>
<p>in the sense that it might cause breakage?</p>
</blockquote>
<p>no, the bug itself</p>



<a name="182673175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673175">(Dec 05 2019 at 15:57)</a>:</h4>
<p>because multiple issues have identified it as injecting a bug</p>



<a name="182673204"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673204" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673204">(Dec 05 2019 at 15:57)</a>:</h4>
<p>see e..g this comment: <a href="https://github.com/rust-lang/rust/pull/59752#issuecomment-554628486" target="_blank" title="https://github.com/rust-lang/rust/pull/59752#issuecomment-554628486">https://github.com/rust-lang/rust/pull/59752#issuecomment-554628486</a></p>



<a name="182673235"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673235" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673235">(Dec 05 2019 at 15:58)</a>:</h4>
<p>it's been argued some (all?) of those usecases were abusing unspecified behavior</p>



<a name="182673297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673297">(Dec 05 2019 at 15:58)</a>:</h4>
<blockquote>
<p>this is nominated for revert</p>
</blockquote>
<p>it's actually nominated for confirming that we don't want to revert because it breaks projects that relied on unspecified behavior</p>



<a name="182673326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673326">(Dec 05 2019 at 15:58)</a>:</h4>
<p>that... was not my reading</p>



<a name="182673336"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673336" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673336">(Dec 05 2019 at 15:58)</a>:</h4>
<p>let me go double-check</p>



<a name="182673345"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673345" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673345">(Dec 05 2019 at 15:58)</a>:</h4>
<p>plus for finding people that can help look into whether there are actual bugs there</p>



<a name="182673357"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673357" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673357">(Dec 05 2019 at 15:58)</a>:</h4>
<p>" It looks like we should do something. It's not clear to me, however, if the reported breakage is due to code relying on unspecified implementation details or if this should be considered a bug."</p>



<a name="182673395"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673395" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673395">(Dec 05 2019 at 15:59)</a>:</h4>
<p>this bug certainly sounds scary: "<code>dylib</code> shared libraries will not make public symbols that may be necessary to link inlined code" <a href="https://github.com/rust-lang/rust/issues/65610" target="_blank" title="https://github.com/rust-lang/rust/issues/65610">#65610</a></p>



<a name="182673416"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673416">(Dec 05 2019 at 15:59)</a>:</h4>
<p><span class="user-mention" data-user-id="116466">@Zoxc</span> wrote:</p>
<blockquote>
<p><a href="https://github.com/rust-lang/rust/issues/66265" target="_blank" title="https://github.com/rust-lang/rust/issues/66265">#66265</a> seems like it should result in a linker error even if <code>exit</code> was exported from Rust since there's multiple definitions of <code>exit</code>. It's not really something that should be supported without explicit support for shadowing symbols (which we don't have).</p>
</blockquote>



<a name="182673536"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673536" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673536">(Dec 05 2019 at 16:00)</a>:</h4>
<p>didn't the PR have some perf wins also?</p>



<a name="182673543"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673543" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673543">(Dec 05 2019 at 16:00)</a>:</h4>
<p>yeah, this just affects a number of things that we don't specify anywhere, so we need a team-wide decision on what to do about breakage</p>



<a name="182673560"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673560" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673560">(Dec 05 2019 at 16:00)</a>:</h4>
<p>okay, how about this</p>



<a name="182673563"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673563" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673563">(Dec 05 2019 at 16:00)</a>:</h4>
<p>in principle the PR is the right thing to do</p>



<a name="182673568"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673568" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673568">(Dec 05 2019 at 16:00)</a>:</h4>
<p>I just finished investing a nasty inlining bug</p>



<a name="182673582"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673582" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673582">(Dec 05 2019 at 16:00)</a>:</h4>
<p>I'll assign myself to look at these three bugs</p>



<a name="182673590"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673590" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673590">(Dec 05 2019 at 16:01)</a>:</h4>
<p>or at least <a href="https://github.com/rust-lang/rust/issues/65610" target="_blank" title="https://github.com/rust-lang/rust/issues/65610">#65610</a></p>



<a name="182673604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673604">(Dec 05 2019 at 16:01)</a>:</h4>
<p><del>@<strong>pnkfelix</strong> I think that issue is about FFI-ing to a <code>dylib</code>, which isn't supported explicitly</del></p>



<a name="182673606"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673606" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673606">(Dec 05 2019 at 16:01)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> aren't you over-extended as-is?</p>



<a name="182673623"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673623" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673623">(Dec 05 2019 at 16:01)</a>:</h4>
<p><span class="user-mention" data-user-id="126931">@centril</span> of course I am</p>



<a name="182673625"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673625" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673625">(Dec 05 2019 at 16:01)</a>:</h4>
<p>(or maybe you should drop something else)</p>



<a name="182673635"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673635" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673635">(Dec 05 2019 at 16:01)</a>:</h4>
<p><del>I don't think Rust dependencies are broken</del></p>



<a name="182673642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673642">(Dec 05 2019 at 16:01)</a>:</h4>
<p>I'm hoping to tie off two items today</p>



<a name="182673649"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673649" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673649">(Dec 05 2019 at 16:01)</a>:</h4>
<p>maybe a third tomorrow</p>



<a name="182673714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673714">(Dec 05 2019 at 16:02)</a>:</h4>
<p>I'm volunteering to spend a fixed amount of time on <a href="https://github.com/rust-lang/rust/issues/64340" target="_blank" title="https://github.com/rust-lang/rust/issues/64340">https://github.com/rust-lang/rust/issues/64340</a></p>



<a name="182673739"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673739" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673739">(Dec 05 2019 at 16:02)</a>:</h4>
<p>so we're over time (again)</p>



<a name="182673753"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673753" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673753">(Dec 05 2019 at 16:02)</a>:</h4>
<p>I was hoping to get a checkin from <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> on WG-learning</p>



<a name="182673771"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673771" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673771">(Dec 05 2019 at 16:02)</a>:</h4>
<p>wait, the <a href="https://github.com/rust-lang/rust/issues/65610" target="_blank" title="https://github.com/rust-lang/rust/issues/65610">#65610</a> example is about a <em>C library</em> being privatized behind a <code>dylib</code>?!</p>



<a name="182673783"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673783" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673783">(Dec 05 2019 at 16:03)</a>:</h4>
<h1>WG-Learning check-in (2019-12-05)</h1>
<p>Acomplished:</p>
<p>- We have a <a href="https://github.com/rust-lang/rustc-guide/pull/529" target="_blank" title="https://github.com/rust-lang/rustc-guide/pull/529">chapter about Salsa</a>, it was summarized from <a href="https://www.youtube.com/watch?v=_muY4HjSqVw" target="_blank" title="https://www.youtube.com/watch?v=_muY4HjSqVw">this lecture</a><br>
- We have a <a href="https://github.com/rust-lang/rustc-guide/pull/530" target="_blank" title="https://github.com/rust-lang/rustc-guide/pull/530">PR for the ty chapter PR</a>, it summarizes <a href="https://www.youtube.com/watch?v=c01TsOsr3-c" target="_blank" title="https://www.youtube.com/watch?v=c01TsOsr3-c">this lecture</a><br>
- We had a <a href="#narrow/stream/196385-t-compiler.2Fwg-learning/topic/planning.20meeting" title="#narrow/stream/196385-t-compiler.2Fwg-learning/topic/planning.20meeting">planning meeting</a>, where we come up with a <a href="https://hackmd.io/iamkyR_QTdSIdGjYQX_XjQ" target="_blank" title="https://hackmd.io/iamkyR_QTdSIdGjYQX_XjQ">document with ideas and next steps</a> for the rustc-guide. We've basically defined kind of a roadmap and a way to work towards those goals.</p>
<p>Next steps:</p>
<p>- Start writing an Overview chapter<br>
- Organize a lecture about codegen mir -&gt; llvm IR  (<span class="user-mention" data-user-id="123586">@nagisa</span>, maybe?)<br>
- Organize a lecture about LLVM (<span class="user-mention" data-user-id="116015">@Alex Crichton</span>, maybe?)<br>
- Organize a lecture about monomorphization/type memory layout (<span class="user-mention" data-user-id="124288">@oli</span>, maybe?)</p>



<a name="182673848"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673848" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673848">(Dec 05 2019 at 16:03)</a>:</h4>
<p>Wow, that's awesome progress</p>



<a name="182673854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673854">(Dec 05 2019 at 16:03)</a>:</h4>
<p>Thanks <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> !</p>



<a name="182673915"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673915" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673915">(Dec 05 2019 at 16:04)</a>:</h4>
<p><span class="user-mention" data-user-id="123586">@nagisa</span> I assume there's nothing to report from WG-llvm (since you posted recently there that maybe it needs to change its classification)</p>



<a name="182673937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673937">(Dec 05 2019 at 16:04)</a>:</h4>
<p>Yeah.</p>



<a name="182673945"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673945" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> mw <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673945">(Dec 05 2019 at 16:04)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> oh sorry, btw, for never replying to your message. I don't have time to prepare lectures but I can do a Q&amp;A on zulip if that helps</p>



<a name="182673953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673953">(Dec 05 2019 at 16:04)</a>:</h4>
<p>(Question: are we going to be discussing the linking breakage in a separate topic?)</p>



<a name="182673978"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673978" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673978">(Dec 05 2019 at 16:04)</a>:</h4>
<blockquote>
<p>(Question: are we going to be discussing the linking breakage in a separate topic?)</p>
</blockquote>
<p>we probably should. lets fork that off</p>



<a name="182673993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182673993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182673993">(Dec 05 2019 at 16:05)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> do you have thoughts on how to proceed with the overview chapter?</p>



<a name="182674024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674024">(Dec 05 2019 at 16:05)</a>:</h4>
<p>It seems like that would require some interaction with an expert, and I'm curious if you all discussed an idea of what it looks like</p>



<a name="182674040"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674040" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674040">(Dec 05 2019 at 16:05)</a>:</h4>
<p>also I will try to proof read <a href="https://github.com/rust-lang/rustc-guide/issues/530" target="_blank" title="https://github.com/rust-lang/rustc-guide/issues/530">rust-lang/rustc-guide#530</a></p>



<a name="182674111"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674111" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674111">(Dec 05 2019 at 16:06)</a>:</h4>
<p>spawned off <a href="#narrow/stream/131828-t-compiler/topic/dylib.20linking.20breakage/near/182674053" title="#narrow/stream/131828-t-compiler/topic/dylib.20linking.20breakage/near/182674053">https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/dylib.20linking.20breakage/near/182674053</a></p>



<a name="182674119"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674119" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674119">(Dec 05 2019 at 16:06)</a>:</h4>
<blockquote>
<p>also I will try to proof read <a href="https://github.com/rust-lang/rustc-guide/issues/530" target="_blank" title="https://github.com/rust-lang/rustc-guide/issues/530">rust-lang/rustc-guide#530</a></p>
</blockquote>
<p>I can let you know when that should be proof read, we are polishing a very tiny thing</p>



<a name="182674144"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674144" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674144">(Dec 05 2019 at 16:06)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> speaking of docs and learning... I was thinking of adding some typing rules to e.g. <code>check_expr_foobarkind</code> -- I started a bit with <a href="https://github.com/Centril/rust/commit/6d2467ddf6ff2901f7e5f3522435d635db2daa9f" target="_blank" title="https://github.com/Centril/rust/commit/6d2467ddf6ff2901f7e5f3522435d635db2daa9f">https://github.com/Centril/rust/commit/6d2467ddf6ff2901f7e5f3522435d635db2daa9f</a> but maybe that's not the right approach there... we sorta mainly have synthesizing bidirectional judgements but with hints...</p>



<a name="182674147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674147">(Dec 05 2019 at 16:06)</a>:</h4>
<p>it may be ready tomorrow maybe, but I'd let you know</p>



<a name="182674172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674172">(Dec 05 2019 at 16:06)</a>:</h4>
<p>could use some input <span aria-label="slight smile" class="emoji emoji-1f642" role="img" title="slight smile">:slight_smile:</span></p>



<a name="182674212"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674212" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674212">(Dec 05 2019 at 16:07)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="116266">Santiago Pastorino</span> do you have thoughts on how to proceed with the overview chapter?</p>
</blockquote>
<p>about this we have ... <a href="https://hackmd.io/j8EsXGI1RiOnjZSiSRf3ng" target="_blank" title="https://hackmd.io/j8EsXGI1RiOnjZSiSRf3ng">https://hackmd.io/j8EsXGI1RiOnjZSiSRf3ng</a></p>



<a name="182674225"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674225" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674225">(Dec 05 2019 at 16:07)</a>:</h4>
<p><span class="user-mention" data-user-id="126931">@centril</span> you should probably use a different case convention for judgements than expressions and types</p>



<a name="182674244"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674244" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674244">(Dec 05 2019 at 16:07)</a>:</h4>
<p>we'd definitely need help, I'm going to ping somebody about it soon, the idea was to start with something first</p>



<a name="182674287"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674287" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674287">(Dec 05 2019 at 16:07)</a>:</h4>
<p><code>IsPlaceExpr(lhs)</code> or some variant thereof looks nicer IMO</p>



<a name="182674340"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674340" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> eddyb <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674340">(Dec 05 2019 at 16:08)</a>:</h4>
<p><code>lhs IsPlaceExpr</code></p>



<a name="182674347"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674347" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674347">(Dec 05 2019 at 16:08)</a>:</h4>
<blockquote>
<p>we'd definitely need help, I'm going to ping somebody about it soon, the idea was to start with something first</p>
</blockquote>
<p>ok</p>



<a name="182674358"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674358" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674358">(Dec 05 2019 at 16:08)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <span class="user-mention silent" data-user-id="116266">Santiago Pastorino</span> speaking of docs and learning... I was thinking of adding some typing rules to e.g. <code>check_expr_foobarkind</code> -- I started a bit with <a href="https://github.com/Centril/rust/commit/6d2467ddf6ff2901f7e5f3522435d635db2daa9f" target="_blank" title="https://github.com/Centril/rust/commit/6d2467ddf6ff2901f7e5f3522435d635db2daa9f">https://github.com/Centril/rust/commit/6d2467ddf6ff2901f7e5f3522435d635db2daa9f</a> but maybe that's not the right approach there... we sorta mainly have synthesizing bidirectional judgements but with hints...</p>
</blockquote>
<p><span class="user-mention" data-user-id="126931">@centril</span> why don't you write a bigger rustc-guide chapter <span aria-label="smiley" class="emoji emoji-1f603" role="img" title="smiley">:smiley:</span></p>



<a name="182674376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674376">(Dec 05 2019 at 16:08)</a>:</h4>
<p>I've been thinking that it makes sense to base it on a particular example</p>



<a name="182674391"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674391" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674391">(Dec 05 2019 at 16:08)</a>:</h4>
<p><span class="user-mention" data-user-id="119009">@eddyb</span> probably; needs a lot of iteration, and there should probably be a name for the rule on the <code>-----</code> line</p>



<a name="182674394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674394">(Dec 05 2019 at 16:08)</a>:</h4>
<p>yes</p>



<a name="182674424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674424">(Dec 05 2019 at 16:08)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span>  I wanted inline comments in the code as a start to keep it updated</p>



<a name="182674449"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674449" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674449">(Dec 05 2019 at 16:09)</a>:</h4>
<p>anyway ok over time for meeting I guess :) very cool stuff!</p>



<a name="182674452"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674452" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674452">(Dec 05 2019 at 16:09)</a>:</h4>
<p>(I'll take a look, <span class="user-mention" data-user-id="126931">@centril</span>)</p>



<a name="182674466"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182674466" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182674466">(Dec 05 2019 at 16:09)</a>:</h4>
<p>thanks</p>



<a name="182675053"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182675053" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182675053">(Dec 05 2019 at 16:15)</a>:</h4>
<p>yeah. bye to everyone in <span class="user-group-mention" data-user-group-id="897">@T-compiler/meeting</span> ! Thanks for attending. I gotta go do child care now</p>



<a name="182686046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/weekly%20meeting%202019-12-05%20%2354818/near/182686046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Manish Goregaokar <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/weekly.20meeting.202019-12-05.20.2354818.html#182686046">(Dec 05 2019 at 18:07)</a>:</h4>
<p>Yeah the diagnostics stuff is in <a href="https://github.com/rust-lang/rust/issues/61132" target="_blank" title="https://github.com/rust-lang/rust/issues/61132">https://github.com/rust-lang/rust/issues/61132</a> , we just need to implement that syntax extension</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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